Flyfish Fanatic

Just saw an article in a local rag about a huge problem. It seems like  there may have been a problem with the dam on the Stave river in Mission BC, Canada. Read this articale for more, I hope it is not as bad as it sounds, I fish in this river every year and this would be a huge hit to the Salmon in the area.

This is the Full article:

By Phil Melnychuk
Staff Reporter
Mar 03 2007

Fisheries and Oceans Canada is checking into a possible buildup of nitrogen in the Stave River that may have killed millions of young coho and chum salmon.

A drawdown of B.C. Hydro’s Hayward reservoir Feb. 13 to allow inspection on the Ruskin dam may have been the cause, said Hydro community relations spokesman Charlotte Bemister.

“As a result of lowering the reservoir and the build-up of debris, that may have allowed air to get into the water. Therefore, it’s suspected that that may be the cause, but it’s still very much suspected.”

Lowering the reservoir is a routine practice, but Bemister didn’t know how often a gas buildup results from that.

Hydro sent out a biologist to investigate Feb. 15 and found about 100 dead bullhead, or sculpin, fish.

Angler Troy Halliday was on the river at the time and saw about 30 to 40 dead bullhead washed up on the beach.

“That was three weeks ago, but nobody’s said anything about it,” he said.

Now he’s wondering about the extent of the fish kill, how many eggs have been killed and the effects on steelhead and cutthroat trout.

“It concerns me. In order to have killed some fish it would have to be a pretty big spill.”

Normally, the Stave River runs fairly clearly, but on Feb. 13, it had a greenish tinge, Halliday said.

He saw one steelhead trout thrashing around with bloodshot eyes, bleeding from its gills.

Bemister said Hydro is working with Fisheries and Oceans Canada, studying the coho and chum “redds,” or nests, in the river gravel below the dam and checking on the mortality of the alevins, or young salmon, that would have just developed from eggs.

The event happened at the worst time of the year, said Geoff Clayton of the Alouette River Management Society.

Chum and coho are in the alevin stage in February, when the tiny fish have just broken free from their eggs but are still attached to the yolks for nutrition.

The fish at that point are breathing, “so they’re subject to any toxin in the water,” but unable to swim away.

“Their redds, which has been their haven, could have potential to be their coffin,” Clayton said.

In a few weeks, the juveniles would be free from the eggs and the chum would able to swim down the Stave to the Fraser River.

Preliminary results from Fisheries and Oceans Canada testing, after scientists dug up 17 redds, showed a death rate of one in seven, he said. More testing in the coming weeks will show if those deaths were caused by an “event kill,” he added.

Lowering the reservoir level for maintenance is a routine practice, but this occasion might have surprised everyone.

Clayton’s not saying Hydro did anything abnormal or irresponsible. “They really don’t know what happened, but it is assumed that a vortex developed.”

That vortex, similar to what happens when water drains down a sink, may have been caused by debris at the top. That could have entrained air into the water in the spill tunnel and caused higher nitrogen levels in the water and produced effects similar to what happens to a diver who surfaces too quickly with the bends.

“Supersaturated” nitrogen levels don’t dissipate quickly, Clayton said.

“It could be half a mile downstream and still be lethal.”

I hope for good news in the future, this would be devistating.

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